U.S. patent number 5,700,281 [Application Number 08/668,117] was granted by the patent office on 1997-12-23 for stage and state monitoring automated external defibrillator.
This patent grant is currently assigned to SurVivaLink Corporation. Invention is credited to James E. Brewer, Kenneth F. Olson, Gary B. Stendahl, John F. Stolte, Nora J. Utke.
United States Patent |
5,700,281 |
Brewer , et al. |
December 23, 1997 |
**Please see images for:
( Certificate of Correction ) ** |
Stage and state monitoring automated external defibrillator
Abstract
A circuit detectable arrangement of a plurality of medical
electrodes is provided with each electrode having an electrically
nonconductive backing layer, a layer of electrically conductive
adhesive disposed on the backing layer and a lead wire extending
therefrom and electrically connected with the conductive adhesive.
More specifically, a first electrode is disposed on an electrically
nonconductive liner, a second electrode is disposed on an
electrically nonconductive liner, and an electrical connector is
provided between the first and second electrodes for electrically
completing a circuit connecting the lead wire of the first
electrode to the lead wire of the second electrode. Preferably, the
backing layers of the first and second electrodes each include a
conductor portion, and the electrical connector is connected
between the conductor portion of the backing layer of the first
electrode and the conductor portion of the backing layer of the
second electrode. The electrical connector preferably comprises a
strip of flexible and electrically conductive material and may
include a nonconductive tear resistant strip. Utilizing the
electrode packaging above, the present invention monitors the state
of the AED and the stage of a rescue. In particular, at least five
stages of a rescue are monitored. These include: 1) rescue
initiated; 2) preparing victim; 3) applying electrodes; 4) AED in
use; and 5) rescue completed.
Inventors: |
Brewer; James E. (St. Paul,
MN), Olson; Kenneth F. (Edina, MN), Stolte; John F.
(Burnsville, MN), Utke; Nora J. (Minneapolis, MN),
Stendahl; Gary B. (Crystal, MN) |
Assignee: |
SurVivaLink Corporation
(Minneapolis, MN)
|
Family
ID: |
46251068 |
Appl.
No.: |
08/668,117 |
Filed: |
June 17, 1996 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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658200 |
Jun 4, 1996 |
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Current U.S.
Class: |
607/5; 607/142;
607/152 |
Current CPC
Class: |
A61N
1/3931 (20130101); A61N 1/04 (20130101) |
Current International
Class: |
A61N
1/04 (20060101); A61N 1/39 (20060101); A61N
1/08 (20060101); A61N 001/39 (); A61N 001/04 ();
A61N 001/08 () |
Field of
Search: |
;607/5,8,142,152 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Kamm; William E.
Assistant Examiner: Layno; Carl H.
Attorney, Agent or Firm: Patterson & Keough, P.A.
Parent Case Text
RELATED APPLICATIONS
The present invention is a continuation-in-part of co-pending U.S.
patent application Ser. No. 08/658,200 entitled Circuit Detectable
Packaged Medical Electrodes, filed Jun. 4, 1996.
Claims
What is claimed is:
1. An automated external defibrillator (AED) having a packaged pair
of electrodes electrically connected together, wherein the AED is
capable of monitoring the state it is in, the AED comprising:
a case;
an electrode terminal mounted to the case;
a high voltage circuit contained in the case and electrically
connected to the electrode terminal; and
a control system coupled to the electrode terminal and the high
voltage circuit wherein the control system includes state detection
means for determining the state of the AED, said states being (1)
the AED is being used for a rescue and (2) the AED is not being
used for a rescue.
2. The AED of claim 1, the AED being capable of performing a
cardiac arrest rescue procedure on a patient, the rescue procedure
having a plurality of rescue stages, wherein the control system
further comprises impedance monitoring means for monitoring the
specific stages of a cardiac arrest rescue procedure.
3. The AED of claim 1, the AED being capable of performing a
cardiac arrest rescue procedure on a patient, the rescue procedure
having a plurality of rescue stages, wherein the control system
further comprises rescue stage monitoring means for monitoring the
specific stages of a cardiac arrest rescue procedure.
4. The AED of claim 3 wherein the packaged pair of electrodes
comprises a package of flexible material defining a pouch having an
interior cavity including first and second medical electrodes
within an electrode receiving space of said interior cavity, each
electrode comprising an electrically non-conductive flexible
backing layer, a layer of electrically conductive adhesive disposed
on said flexible backing layer and a lead wire extending therefrom
and electrically connected with said conductive adhesive, wherein
said first and second electrodes are each disposed on an
electrically non-conductive liner, and an electrical connector is
provided between said first and second electrodes for electrically
completing a circuit connecting the lead wire of said first
electrode to the lead wire of said second electrode.
5. The AED of claim 4, wherein the lead wires from said first and
second electrodes extend through an opening provided through said
package to the outside of said package.
6. The AED of claim 5, further including a tear line along which
the package is to be opened and which divides the interior cavity
of the package into said electrode receiving space and an interior
portion.
7. The AED of claim 4 wherein the liners of the first and second
electrodes have a plurality of holes formed therein.
8. An automated external defibrillator (AED) having a packaged pair
of electrodes electrically connected together, wherein the AED is
capable of monitoring the state it is in, the AED comprising:
a case;
an electrode terminal mounted to the case;
a high voltage circuit contained in the case and electrically
connected to the electrode terminal; and
a control system coupled to the electrode terminal and the high
voltage circuit wherein the control system includes state detection
means for determining the state of the AED and further includes
rescue stage monitoring means for monitoring the stage of a
rescue
the packaged pair of electrodes having a package of flexible
material defining a pouch having an interior cavity including first
and second medical electrodes within an electrode receiving space
of said interior cavity, the package including a tear line along
which the package is to be opened and which divides the interior
cavity of the package into said electrode receiving space and an
interior portion, each electrode comprising an electrically
non-conductive flexible backing layer, a layer of electrically
conductive adhesive disposed on said flexible backing layer and a
lead wire extending therefrom and electrically connected with said
conductive adhesive, wherein said first and second electrodes are
each disposed on an electrically non-conductive liner, and an
electrical connector is provided between said first and second
electrodes for electrically completing a circuit connecting the
lead wire of said first electrode to the lead wire of said second
electrode, the lead wires from said first and second electrodes
extending through an opening provided through said package to the
outside of said package.
9. The AED of claim 8 wherein said electrical connector comprises a
flexible conductive strip, and said first and second electrodes are
provided adjacent to one another in said package with their backing
layers generally parallel to one another and with a loop formed in
the electrical connector, said loop extending across said tear line
and into said interior portion of said package from said electrodes
within said electrode receiving space so that by opening the
package along said tear line, the electrical connector can be
broken, said first electrode being provided on a separate liner
than the liner of said second electrode.
10. The AED of claim 8, wherein said electrical connector comprises
a flexible conductive strip, and said first and second electrodes
are provided adjacent to one another in said package with their
backing layers generally parallel to one another and with a loop
formed in the electrical connector, said loop extending across said
tear line and into said interior portion of said package from said
electrodes within said electrode receiving space so that by opening
the package along said tear line, the electrical connector can be
broken.
11. The AED of claim 10, further including a strip of tear
resistant material connected to said electrical connector and
positioned within said interior portion.
12. The AED of claim 11, wherein said strip of tear resistant
material extends through an opening of said package to provide a
gripping means to facilitate easy opening of said package.
13. The AED of claim 10, wherein said flexible conductive strip
includes a portion extending transverse from said loop and which
extends through an opening of said package to provide a gripping
means to facilitate easy opening of said package.
14. The AED of claim 10, wherein at least one of said lead wires is
disposed within said package through said loop and within said
interior portion so as to pass through the material of said package
from said interior portion.
15. The AED of claim 10, wherein said first electrode is provided
on a separate liner than the liner of said second electrode.
16. The AED of claim 10, wherein the backing layers of said first
and second electrodes each include a conductor portion, and said
electrical connector is connected between the conductor portion of
the backing layer of said first electrode and the conductor portion
of the backing layer of said second electrode.
17. The AED of claim 16, wherein the lead wire of each electrode
extends partially within the electrode between the backing layer
and the conductive adhesive, and a terminal is provided to
electrically connect the lead wire within the electrode to the
conductor portion of the backing layer.
18. The AED of claim 8, wherein said electrical connector comprises
a flexible conductive strip, and said first and second electrodes
are provided adjacent to one another in said package with their
backing layers generally parallel to one another and with a loop
formed in the electrical connector, said loop extending across said
tear line and into said interior portion of said package from said
electrodes within said electrode receiving space so that by opening
the package along said tear line, the electrical connector can be
broken, at least one of said lead wires being disposed within said
package through said loop and within said interior portion so as to
pass through the material of said package from said interior
portion.
19. An automated external defibrillator (AED) having a packaged
pair of electrodes electrically connected together, the AED being
capable of performing a cardiac arrest rescue procedure on a
patient, the rescue procedure having a plurality, of rescue stages,
the AED comprising:
a case;
an electrode terminal mounted to the case;
a high voltage circuit contained in the case and electrically
connected to the electrode terminal; and
a control system coupled to the electrode terminal and the high
voltage circuit wherein the control system includes stage
monitoring means for monitoring the specific stages of a cardiac
arrest rescue procedure.
20. The AED of claim 19 wherein the control system further
comprises state detection means for determining the state of the
AED, said states being (1) the AED is being used for a rescue and
(2) the AED is not being used for a rescue.
21. The AED of claim 20 wherein the packaged pair of electrodes
comprises a package of flexible material defining a pouch having an
interior cavity including first and second medical electrodes
within an electrode receiving space of said interior cavity, each
electrode comprising an electrically non-conductive flexible
backing layer, a layer of electrically conductive adhesive disposed
on said flexible backing layer and a lead wire extending therefrom
and electrically connected with said conductive adhesive, wherein
said first and second electrodes are each disposed on an
electrically non-conductive liner, and an electrical connector is
provided between said first and second electrodes for electrically
completing a circuit connecting the lead wire of said first
electrode to the lead wire of said second electrode.
22. The AED of claim 19 wherein the control system monitors at
least the rescue stages of (1) rescue initiated, (2) preparing
victim, (3) applying electrodes, (4) AED in use, and (5) rescue
completed.
23. The AED of claim 22 wherein the rescue stages monitored
correspond to sensed impedances as follows: (1) rescue initiated
being less than about ten ohms, (2) preparing victim being greater
than about two hundred-fifty ohms and less than about one thousand
ohms, (3) applying electrodes being greater than ten kilo ohms, (4)
AED in use being between about twenty-five ohms and two hundred
ohms, and (5) rescue completed being greater than ten kilo
ohms.
24. An automated external defibrillator (AED) having a packaged
pair of electrodes electrically connected together, wherein the AED
is capable of monitoring the state it is in, the AED
comprising:
a case;
an electrode terminal mounted to the case;
a high voltage circuit contained in the case and electrically
connected to the electrode terminal; and
a control system coupled to the electrode terminal and the high
voltage circuit wherein the control system includes an AED power
on/AED power off detection portion.
25. The AED of claim 24 wherein the control system further
comprises a rescue stage identifying and monitoring portion.
26. An automated external defibrillator (AED) having a packaged
pair of electrodes electrically connected together, wherein the AED
is capable of monitoring the state it is in, the AED
comprising:
a case;
an electrode terminal mounted to the case;
a high voltage circuit contained in the case and electrically
connected to the electrode terminal; and
a control system coupled to the electrode terminal and the high
voltage circuit wherein the control system includes a rescue stage
identifying and monitoring portion and an AED power on/AED power
off detection portion.
27. A method of monitoring the stage of a rescue procedure
utilizing an automated external defibrillator (AED) having rescue
stage monitoring means wherein the AED has a case, an electrode
terminal mounted to the case, a high voltage circuit contained in
the case and electrically connected to the electrode terminal, and
a control system coupled to the electrode terminal and the high
voltage circuit wherein the control system includes the stage
monitoring means, and wherein the control system contains an
internal clock and memory means, the method including the steps
of:
(a) polling the AED to determine if the AED is on;
(b) using the internal clock to identify when the AED is turned
on;
(c) storing in the memory means the time from the internal clock
when the AED is turned on;
(d) measuring the resistance at the electrode terminal;
(e) determining a rescue stage from the measured resistance;
(f) identifying the time the rescue stage began with the internal
clock; and
(g) recording in the memory means the time of the rescue stage.
28. The method of claim 27 further including the step of:
(h) repeating steps (c) through (g) until the rescue is
completed.
29. An automated external defibrillator (AED) having a packaged
pair of electrodes electrically connected together, wherein the AED
is capable of monitoring the state it is in, the AED
comprising:
a case;
an electrode terminal mounted to the case;
a high voltage circuit contained in the case and electrically
connected to the electrode terminal; and
a control system coupled to the electrode terminal and the high
voltage circuit wherein the control system includes an AED power
on/AED power off detection portion and further includes a rescue
stage identifying and monitoring portion.
30. An automated external defibrillator (AED) having a packaged
pair of electrodes electrically connected together, the AED being
capable of performing a cardiac arrest rescue procedure on a
patient, the rescue procedure having a plurality of rescue stages,
the AED comprising:
a case;
an electrode terminal mounted to the case;
a high voltage circuit contained in the case and electrically
connected to the electrode terminal; and
a control system coupled to the electrode terminal and the high
voltage circuit wherein the control system includes impedance
monitoring means for monitoring the specific stages of a cardiac
arrest rescue procedure.
31. The AED of claim 30 wherein the control system further
comprises state detection means for determining the state of the
AED, said states being (1) the AED is being used for a rescue and
(2) the AED is not being used for a rescue.
Description
FIELD OF THE INVENTION
The present invention relates to automated external defibrillators
(AEDs). In particular, the present invention is an AED capable of
monitoring the state of the AED and the stage of a rescue.
BACKGROUND OF THE INVENTION
Electrodes are used with numerous devices in the medical field. One
such application is with an automated external defibrillator (AED).
AEDs are used by first-responder emergency medical technicians to
resuscitate cardiac arrest patients. It is important that AEDs
carried by these technicians be continuously operational and ready
for use on a moment's notice. To help ensure a high level of
confidence that they will be operational when needed, AEDs must be
periodically checked and tested by the technicians, and corrective
maintenance performed if any faults are identified. AED's functions
and components that should be periodically checked and tested, for
example, include the charge state of batteries, the presence of
electrodes and the ability of the device to charge and deliver
defibrillation pulses.
An automated external defibrillator with self-test system has been
developed and is disclosed in co-pending U.S. patent application
Ser. No. 08/512,441, entitled "Automated External Defibrillator
with Self-Test System," which is commonly assigned to the assignee
of the subject application, and the entire contents of which are
incorporated herein by reference. Disclosed is a defibrillator that
includes a digital control system having self-test means for
periodically and automatically performing self-tests of one or more
defibrillator components. If a malfunctioning component is
identified, the self-test means actuates an audible alarm or other
maintenance indicator to alert an operator. Specifically tested
functions include the presence and interconnection of defibrillator
electrodes, battery-charge state, the functionality of the high
voltage circuit and the functionality of the digital control
system. Some functions are self-tested daily, while others are
self-tested weekly.
In order to test the presence and interconnection of defibrillator
electrodes, the defibrillator electrodes must be packaged or
otherwise arranged in a way to permit the testing. Specifically, it
is described in the aforementioned co-pending application Ser. No.
08/512,441 that a pair of electrodes together form a part of an
electric circuit through which current is run during the self-test
and the impedance measured. A relatively low impedance, (e.g., less
than about 10 ohms) indicates the presence of a pair of electrodes.
In order for the electrodes to make up and complete an electrical
circuit, both electrodes are electrically connected with one
another so that a circuit can comprise the electrical lead wires of
each electrode. To do this, the electrically conducive adhesive
layers of each of the pair of electrodes are affixed in a
face-to-face orientation to opposite sides of a release liner
within a package. The release liner is perforated with a number of
apertures so that the electrodes are electrically coupled to one
another within the package. A relatively low resistance electrical
circuit is thereby established between the ends of the lead
wires.
The above-described system effectively detects the presence of a
pair of electrodes as provided in the package. An additional
advantage is that the freshness of the packaged electrodes can be
determined because the conductive adhesive layers increase in
resistance as they dry out over time. However, a problem that the
circuit cannot distinguish between is new electrodes and electrodes
that have been used or tampered with and subsequently stuck back
together, with or without the perforated release liner.
Additionally, the circuit cannot determine what stage an ongoing
rescue is in.
Medical electrode packaging is also described in U.S. Pat. No.
5,402,884 to Gilman, et al., which is assigned to the assignee of
the present invention. In one embodiment, a sealed package is
disclosed containing a pair of medical electrodes with conductive
adhesive layers facing one another and separated from one another
by a resistive layer. A circuit can be completed through the lead
wires of each electrode, through the conductive adhesive of each
electrode, and through the resistive layer. Again, by monitoring
resistance through the circuit, the presence of the electrodes can
be detected. Also disclosed in the Gilman, et al. patent are a
number of other packages for single medical electrodes. In each
case, at least one conductor is provided through the package so
that a circuit can be completed through the package and a portion
of the conductive adhesive layer of the one electrode. While these
packages are useful for their intended purpose, further information
about the AED and the rescue is desirable.
SUMMARY OF THE INVENTION
In accordance with the present invention, an automated external
defibrillator (AED) having a circuit detectable arrangement of
medical electrodes and a package thereof is provided that overcome
the disadvantages and shortcomings of the prior art. Specifically,
the AED of the present invention can detect the presence or absence
of a fresh package of electrodes and can also detect the state of
the AED and the stage of an ongoing rescue.
In accordance with one aspect of the present invention, a circuit
detectable arrangement of a plurality of medical electrodes is
provided with each electrode having an electrically nonconductive
backing layer, a layer of electrically conductive adhesive disposed
on the backing layer and a lead wire extending therefrom and
electrically connected with the conductive adhesive. More
specifically, a first electrode is disposed on an electrically
nonconductive liner, a second electrode is disposed on an
electrically nonconductive liner, and an electrical connector is
provided between the first and second electrodes for electrically
completing a circuit connecting the lead wire of the first
electrode to the lead wire of the second electrode. Preferably, the
backing layers of the first and second electrodes each include a
conductor portion, and the electrical connector is connected
between the conductor portion of the backing layer of the first
electrode and the conductor portion of the backing layer of the
second electrode. The electrical connector preferably comprises a
strip of flexible and electrically conductive material and may
include a nonconductive tear resistant strip.
Utilizing the electrode packaging above, the present invention can
monitor the state of the AED and the stage of a rescue. In
particular, at least five stages of a rescue can be monitored.
These include: 1) rescue initiated; 2) preparing victim; 3)
applying electrodes; 4) AED in use; and 5) rescue completed.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of an automated external defibrillator
(AED) with a pair of electrodes according to the present invention
attached thereto.
FIG. 2 is a detailed plan view of unpackaged electrodes positioned
on release liners.
FIG. 3 is a cross-sectional view through the pair of electrodes of
FIG. 2 taken along line 3--3.
FIG. 4 is detailed plan view of a second embodiment of unpackaged
electrodes.
FIG. 5 is a plan view of the electrodes of FIG. 4 folded one on top
of the other and provided within a package shown partially broken
away.
FIG. 6 is a detailed plan view of another embodiment of a pair of
unpackaged electrodes.
FIG. 7 is a plan view of the electrodes of FIG. 6 folded together
and provided within a package shown partially broken away.
FIG. 8 is a block diagram of an electrical system of an AED.
FIG. 9 is a flow diagram of a state monitoring procedure according
to the present invention.
FIG. 10 is a flow diagram of a stage monitoring procedure according
to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention is an automated external defibrillator (AED)
having a circuit detectable arrangement of medical electrodes and a
package therefore.
FIG. 1 illustrates a pair of electrodes 50 connected to an AED 22.
As can be seen in FIG. 1, defibrillator 22 includes a plastic case
24 with a carrying handle 26 on the top portion. An illuminable
rescue switch 28, visual maintenance indicator 30, data
communication port 32 and charging port 34 are located on the
outside of case 24 for easy access by an operator. Case 24 also
includes an electrode compartment 36 which is enclosed by a lid 38
which is mounted to the case by hinges (not shown).
Finger-receiving recess 31 in lid 28 is grasped to open the lid and
access the electrode compartment 36. An electrode connector 40,
speaker 41 and diagnostic display panel 36 are located on case 12
within electrode compartment 26. Diagnostic display panel 37
includes Resume switch 48 and resume indicator light 49.
Defibrillator electrodes 50, as illustrated in FIGS. 1 and 2, each
include a polymer backing layer 52, and a patient-engaging layer 54
of conductive adhesive which overlays the backing layer. In one
embodiment of the electrodes, backing layer 52 is a flexible
polymeric foam. Conductive adhesives for electrode use are
well-known and commercially available, such as Ludlou Technical
Products' conductive hydrogel. A current-dispersing flexible
conductive sheet (not seen in FIG. 1) is preferably located between
backing layer 52 and patient-engaging layer 54 so as to disperse
current over conductive adhesive layer 54. The conductive sheet
need not be the same size as the electrode and is preferably a
homogeneous, solid, thinly deposited metallic substance, or a
conductive ink. Meshes or patterns of conductive adhesives or inks
may be used.
Insulated lead wires 56 extend from each electrode 50, and have a
first end connected within each electrode 50 to its conductive
sheet and a second end connected to a connector 58. Connector 58 is
configured to releasably mate with electrode connector 40 in
electrode compartment 36, as illustrated. Electrodes 50 are sealed
within a polymer or polymer-metal laminate package 60. Lead wires
56 and connector 58 extend from package 60.
A first embodiment of a pair of electrodes 50 to be provided within
package 60 is shown in FIGS. 2 and 3. The package design of FIG. 1
illustrates electrodes 50 folded against one another and provided
within package 60. As shown in FIG. 2, each electrode 50 includes
backing layer 52, patient-engaging layer 54 of conductive adhesive,
a conductive sheet 53 (illustrated in FIG. 3) between layers 52 and
54, and a liner 61. Liner 61 can comprise any conventional lining
material such as plastic sheeting or treated papers. Both
electrodes 50 may be provided together on a single liner sheet;
however, for reasons set out below, other compensations would be
necessary. It should be noted that liner 61 may be comprised of a
solid piece of material or have a plurality of perforations formed
therein.
A lead wire 56 connects with each electrode 50. Specifically, lead
wire 56 extends partially within each electrode 50, preferably
between backing layer 52 and conductive adhesive layer 54. A
terminal 62 is provided at the end of lead wire 56 within each
electrode 50 for preferably connecting the conductive wire of lead
wire 56 to conductive sheet 53. Otherwise, terminal 62 may directly
conduct current to conductive adhesive layer 54.
In accordance with the present invention, each terminal 62
preferably extends through backing layer 52 so as to provide a
conductor 63 at the surface of backing layer 52. Conductors 63 are
connected together electrically by a flexible conductive connector
64. Conductive connector 64 preferably comprises a metal foil or a
fine wire which can be folded for packaging and easily torn or
broken, the reasons for which will be evident from the description
below. Moreover, connector 64 can be conventionally electrically
connected to conductors 63 by conductive adhesive, heat bonding
solder, or the like. Preferably, conductors 63 and conductive
connector 64 are positioned and arranged, such as that illustrated
in FIG. 2, so that when electrodes 50 are to be packaged within
package 60, they can be folded against one another by a fold line
65 bisecting conductive connector 64. By this arrangement, an
electrical circuit can be completed between lead wires 56 through
terminals 62, conductors 63, and connecting conductor 64. Also
preferably provided, is a strip of tear resistant material 66 that
is more preferably provided at about the midpoint of conductor
connector 64 and which extends transverse to the direction of
connector 64. Tear resistance strip 66 may comprise a plastic,
paper or other nonconductive material which is tear resistant as
compared to the material of conductive connector 64.
Referring back to FIG. 1, electrodes 50 are folded toward one
another along fold line 65 and positioned within a pouch type
package 60 that can be conventionally made either of two sheets
connected together or a single sheet folded and sealed at its edges
67. One of sealed edges 67 accommodates the passage of lead wires
56 from package 60 by forming a small opening through the edge.
Preferably also, edge 67 also accommodates passage of a portion of
tear resistant strip 66 from the interior of package 60 to the
outside of package 60. A tear line 69 is also provided along
package 60 dividing interior portion 68 of package 60 from the rest
of the inside of the package that is inhabited by the folded pair
of electrodes. Tear line 69 may be facilitated by a line of
weakening or other means for controlling package opening along tear
line 69. Conductive connector 64 preferably extends within package
60 sufficiently from each electrode 50 into package interior
portion 68 so that tear resistant strip 68 also lies completely
within interior portion 68.
To open package 60, a user is instructed to tear the package along
tear line 69. The portion of tear resistant strip 66 extending from
package 60 can be used for gabbing by the user to open the package.
Otherwise, the user would simply rip along tear line 69. In tearing
open package 60 along tear line 69, conductive connector 64 will be
likewise torn or broken. Thus, by opening package 60, the circuit
between lead wires 56 of electrodes 50 within package 60 will be
broken. The provision of tear resistant strip 66 not only provides
an extension for grabbing to begin opening package 60, it also
ensures that conductive connector 64 will be broken during a
tearing operation. As a result of this construction, the presence
of an unbroken conductive connector 64 and the subsequent breaking
thereof during usage of electrodes 50 can be automatically detected
for determining the presence of fresh electrodes 50.
A second embodiment of a pair of electrodes 200 is illustrated in
FIGS. 4 and 5. Specifically, the construction of each electrode 200
is preferably the same as that described above including a backing
layer, a patient-engaging conductive adhesive layer, and a current
dispersing flexible conducting sheet therebetween. Likewise, lead
wires 56 extend partially within electrodes 200 between the backing
layer and the conductive adhesive layer of each electrode 200 and
are preferably connected with the conductive sheets at terminals
202. Terminals 202 similarly provide conductors 204 at the surface
of the backing layers of each electrode 200. Electrodes 200 are
each provided on separate liners 206. As with the previous
embodiment, a single liner could be used. A pair of electrodes 200
are connected together by a conductive connector 208 specifically
connected from one conductor 204 of one electrode 200 to conductor
204 of another electrode 200. Again, conductors 204 can be
conventionally connected to conductive connector 208 by conductive
adhesive, heat bonding, solder or the like. Conductive connector
208 preferably comprises a thin metal foil. Moreover, in accordance
with this embodiment, conductor connector 208 includes an extension
portion 209 that is preferably integrally formed with conductive
connector 208. Portion 209 extends transversely from conductive
connector 208 preferably at about center fold line 210, and extends
substantially further than the edge of liners 206.
In order to provide electrodes 200 within a package 212, shown in
FIG. 5, the construction and arrangement shown in FIG. 4 is folded
substantially on fold line 210 so that electrodes 200 are
positioned back to back with liners 206 against one another.
Package 212 can be a conventional construction pouch having edge
seals 214 around its periphery. Electrodes 200 are received within
an electrode interior portion 216 which is divided from an interior
portion 218 by a tear line 220. As above, lead wires 56 are
accommodated through one of edge seals 214. Likewise, portion 209
of conductive connector 208 preferably extends sufficiently that it
extends through the same edge seal to facilitate opening of the
package. Conductive connector 208 preferably extends within the
package sufficiently from each electrode 200 into package interior
portion 218 so that portion 209 of conductive connector 208 lies
within interior package portion 218.
Then, to open package 212, a user would simply grasp the package at
or near extension portion 209 and tear the package open along tear
line 220. Extension portion 209 ensures that tearing along tear
line 220 by grasping extension point 209 will tear through
conductive connector 208 and break the circuit between lead wires
56. As above, the function of making and generating the circuit
completed by conductive connection 208 and terminals 202 between
lead wires 56 can be monitored by defibrillator 22, as described
generally below, for determining the presence of fresh electrodes
200.
Yet another embodiment is illustrated in FIGS. 6 and 7. Electrodes
300 are provided which are similarly constructed as the
aforementioned embodiments, including a backing layer, a conductive
adhesive layer and a conductive sheet therebetween. Lead wires 56
are preferably connected with the conductive sheets between the
backing layer and the conductive adhesive layer by terminals 302.
Each terminal 302 also preferably provides a conductor 304 at the
surface of the backing layer of each electrode 300. A pair of
electrodes 300 are connected together by a conductive connector
306, specifically connected at each end to a conductor 304 of a
terminal 302. Again, conventional connection means can be used,
such as conductive adhesives, heat bonding, solder or the like.
Conductive connector 306 may comprise a thin foil, a fine wire, or
the like, but preferably comprises a thin foil. Each electrode 300
is also preferably provided on a separate liner 308. A fold line
310 substantially bisects the conductive connector 306 so that
electrodes 300 can be folded back to back with liners 308 against
one another. Conductive connector 306 completes an electrical
circuit for connecting lead wires 56 by way of terminals 302 and
conductors 304.
Electrodes 300 are positioned within an electrode receiving space
312 of package 314 which may be conventionally constructed with
sealed edges 316. The interior of the package is divided by a tear
line 318 into electrode receiving portion 312 and an interior
portion 320.
In accordance with this embodiment, it is important that at least
one of lead wires 56 be properly threaded within the package so as
to exit package 314 at one of its edge seals 316 from within
interior portion 320 of package 314. Moreover, conductive connector
306 forms a loop that extends within interior portion 320 of
package 314. Preferably, both of lead wires 56 pass through the
loop defined by conductive connector 306 when the electrodes are
positioned back to back as folded along fold line 310. More
particularly, lead wires 56 pass between conductive connector 306
and an edge of a liner 308. Furthermore, conductive connector 306
is sufficiently long so that when the electrodes are folded back to
back, conductive connector 306 forms the loop so as to facilitate
both lead wires 56 within interior portion 320. By this embodiment,
package 314 can be easily opened along tear line 318 by a user
grasping lead wires 56 where they exit package 314 at edge seal
316. Then, tearing the package open along tear line 318 will also
tear or break conductive connector 306. Lead wires 56, in this
case, act as a tear strip facilitating easy opening of package 314.
This construction is advantageous in that in a single action opens
the electrode package, breaks the electrical circuit, and removes
the electrodes from the package. As above, the function of making
and breaking the electrical circuit completed by connector 306
between lead wires 56 can be monitored, as set out below, for
determining the presence of fresh electrodes 300.
As an alternative construction to each of the above-described
embodiments, liners 61, 206 and 308 could instead comprise a single
liner to which both electrodes 50, 200, and 300 respectively, are
adhered. To do this, the liners would also be folded to position
the electrodes within the respective packages. However, in order to
provide that conductive connectors, 64, 208, and 306, respectively,
extend across tear lines 69, 220 and 318, respectively, the
conductive connectors must be of sufficiently greater length than
the distance between the electrodes on the single liner so that
when the single liners are folded, the conductive connectors will
form a loop that extends sufficiently away from the folded edge of
the single liner.
FIG. 8 is a block diagram of electrical system 70 of defibrillator
10. The overall operation of defibrillator 10 is controlled by a
digital microprocessor-based control system 72 which includes a
processor 74 interfaced to program memory 76, data memory 77, event
memory 78 and real time clock 79. The operating program executed by
processor 74 is stored in program memory 76. Electrical power is
provided by a rechargeable twelve volt lead-acid cartridge battery
80 and a nine volt battery 82 which are removably positioned within
the battery compartment and connected to power generation circuit
84. Charging port 34 is coupled to power generation circuit 84,
enabling twelve volt battery 80 to be connected to a twelve volt
vehicle battery (not shown) or a 120 VAC charger (also not shown)
and recharged while mounted within defibrillator 12. Alternatively,
battery 80 can be removed from defibrillator 10 and charged in a
stand-alone charger (not shown).
Power generation circuit 84 is also connected to power control
circuit 88 and processor 74. Power control circuit 88 is connected
to lid switch 90, watch dog timer 92, real time dock 79 and
processor 74. Lid switch 90 is a magnetic read relay switch in one
embodiment, and provides signals to processor 74 indicating whether
lid 38 is open or closed. Data communication port 32 is coupled to
processor 74 for two-way serial data transfer using an RS-232
protocol. Rescue switch 28, maintenance indicator 30, rescue switch
light 29, resume switch 48, diagnostic display panel 37, voice
circuit 94 and piezoelectric audible alarm 96 are also connected to
processor 74. Voice circuit 94 is connected to speaker 41. In
response to voice prompt control signals from processor 74, circuit
94 and speaker 41 generate audible voice prompts.
High voltage generation circuit 86 is also connected to and
controlled by processor 74. Circuits such as 86 are generally
known, and disclosed, for example, in the commonly assigned Persson
et al. U.S. Pat. No. 5,405,361, which is hereby incorporated by
reference. In response to charge control signals provided by
processor 74, high voltage generation circuit 86 is operated in a
charge mode during which one set of semiconductor switches (not
separately shown) cause a plurality of capacitors (also not shown),
to be charged in parallel to the 12 V potential supplied by power
generation circuit 84. Once charged, and in response to discharge
control signals provided by processor 74, high voltage generation
circuit 86 is operated in a discharge mode during which the
capacitors are discharged in series by another set of semiconductor
switches (not separately shown) to produce the high voltage
defibrillation pulses. The defibrillation pulses are applied to the
patient through electrode connector 40 which is connected to the
high voltage generation circuit 86.
Impedance measuring circuit 100 is connected to electrode connector
40 and real time clock 79, and is interfaced to processor 74
through analog-to-digital (A/D) converter 102. Impedance measuring
circuit 100 receives a clock signal having a predetermined
magnitude from clock 79, and applies the signal to electrodes 50,
for example, through connector 40. The magnitude of the clock
signal received back from electrodes 50 through connector 40 is
monitored by impedance measuring circuit 100. An impedance signal
representative of the impedance present across electrode connector
40 is then generated by circuit 100 as a function of the ratio of
the magnitudes of the applied and received clock signals (i.e., the
attenuation of the applied signal). For example, if electrodes 50
within an unopened package 60 are connected by conductive connector
64 and connector 58 is properly connected to connector 40 on
defibrillator 10, a relatively low resistance (e.g., less than
about 10 ohms) should be present across connector 40. If package 60
is opened, connector 58 is not properly connected to connector 40,
or the electrodes are not properly positioned on the patient, a
relatively high resistance (e.g., greater than about two hundred
and fifty ohms) will be present across connector 40. The resistance
across connector 40 will be between about twenty and two hundred
ohms when fresh electrodes 50 are properly positioned on the
patient with good electrical contacts. The impedance signal
representative of the impedance measured by circuit 100 is
digitized by A/D converter 102 and provided to processor 74.
The present invention will be described with particular reference
to AED 22 and electrodes 50 as described and illustrated above. AED
22 of the present invention is programmed to monitor for two basic
states. The first state is when AED 22 is not being used for a
rescue, and the second state is when AED 22 is being used for a
rescue. In the first state, processor 74 initiates and performs a
self-test which will then detect the presence of fresh electrodes
50, as described above. In the second state, when the AED is being
used for a rescue, processor 74 monitors the rescue features. A
sample flow chart of this is illustrated in FIG. 9.
In addition to monitoring the state of the AED, electrodes 50 of
the present invention are coupled with detection means to determine
a specific stage of a cardiac arrest rescue procedure.
Specifically, AED 22 has the ability to determine which of at least
five stages the AED is at during a rescue procedure. These stages
include: 1) rescue initiated; 2) preparing victim; 3) applying
electrodes; 4) AED in use; and 5) rescue completed.
By monitoring the stages of a rescue and the states of the AED, a
dynamic characteristic is added to the static aspect of the AED.
The ability to track the stages and states, allows the AED to
perform comprehensive real-time, rescue checking as well as static
self-checking. For example, one embodiment of the present invention
is to use internal clock 79 to track how long each stage of a
rescue procedure takes. This information is then stored in memory
for future review and statistical analysis as to how to modify and
improve rescue procedures to reduce the time spent in specific
stages of a rescue, and/or to improve the manner in which the time
is used. The time management aspect of the invention provides a
means to assure the quality of a rescue. The more time saved during
a rescue procedure (from the time of collapse to the time of the
first attempt to defibrillate the victim) directly translates into
more lives saved. In general, the likelihood of successful
resuscitation drops ten percent for each additional minute that the
victim is not revived.
The present invention also has an enhanced voice prompting feature
to prompt operators more often. This is because the AED is able to
track the stages of a rescue with some precision, thus it knows
what has been done and what needs to be done next. Examples of
voice prompts include; "please open electrode package", "please
pull electrodes apart", "please place electrodes on patient", "do
not touch patient, analyzing rhythm", and "press flashing button to
deliver shock". Additionally, tracking the stages and states of an
AED allows the AED the ability to know if the electrodes are
reused. For example, the electrodes may not be solidly contacted to
the patient at some time during a rescue. In that case, the device
could include a prompt such as "please check electrodes".
The present invention has the impedance values that indicate what
stage a rescue procedure is in stored in memory such that, if
necessary a rescue procedure can be entered in the middle of any
stage and the AED is able to identify the stage and proceed
accordingly. This is beneficial because there may be times when a
package of electrodes is bad, or an operator destroys a package of
electrodes out of panic or for other reasons. If this happens, a
rescue procedure can be suspended, a new package of electrodes
obtained, and then the rescue resumed or a new rescue started. The
AED recognizes this change and jumps back to the appropriate spot
in the new rescue attempt. Additionally, it is possible that the
AED is accidentally or purposely turned off. If the AED is turned
back on within a predetermined time (for example 15-30 seconds) the
AED can be programmed to continue on from where it left off.
In the first stage, it has been determined that a victim is in
need, or it is believed that a victim is in need, of rescue.
Therefore a rescue attempt is initiated. Lid 38 of AED 22 is
opened, turning on the AED. At this point, the electrode package is
still intact and the impedance reading across connector 40 should
be less than about 10 ohms.
In the second stage, the rescue personnel are preparing the victim
for defibrillation rescue. At this point AED 22 is on, and package
60 has been tom open along tear line 69. As described above,
conductive connector 64 is thus torn, breaking the circuit between
lead wires 56 within package 60. At this stage, electrodes 50 are
still connected together via liner 61. The impedance measured at
connector 40 should be greater than about two hundred and fifty
ohms and less than about one thousand ohms at this point.
In the third stage, the rescue personnel have separated the
electrodes for placement on the victim. With the electrodes
separated, and prior to placing them on the patient, the impedance
measured at connector 40 should be infinite or at least greater
than 10 kilo ohms.
In the fourth stage, electrodes 50 are applied to the patient for
rescue. The impedance measured at this point should be typically
between about twenty five and two hundred ohms, depending on body
size of victim, placement of electrodes on the victim and a
multitude of other factors.
In the fifth stage, the rescue is complete, and electrodes 50 have
been removed from the victim. At this point, the impedance should
once again be measured at infinity or greater than 10 kilo
ohms.
In an alternative embodiment of the present invention, the
impedances measured by AED 22 at the different stages are changed.
For example, if electrodes 50 within an unopened package 60 are
connected by conductive connector 64 and connector 58 is properly
connected to connector 40 on defibrillator 10, a low resistance
(e.g., less than about 1 ohm) should be present across connector
40. If package 60 is opened and electrodes are not yet pulled
apart, the resistance at connector 40 will be between about 2.5 and
ten ohms. If package 60 is opened and the electrodes are pulled
apart, a relatively high resistance (e.g., greater than about two
hundred and fifty ohms) will be present across connector 32. The
resistance across connector 40 will be between about twenty five
and two hundred ohms when fresh electrodes 50 are properly
positioned on the patient with good electrical contacts.
A simplified logic flow chart of one embodiment of a stage
monitoring procedure is illustrated in FIG. 10. Blocks 400, 401 and
402 verify that the AED is on and that the electronic package is
still intact. The time of the rescue being initiated is then
recorded in block 404. Block 406 verifies that the AED is now in
stage two. Block 408 then records this time. Block 410 verifies
that the electrodes are separated and not applied to the victim,
and block 412 records this time. Blocks 414 and 416 verify that the
electrodes have been placed on the victim and records the time.
Finally, blocks 418 and 420 verify that the electrodes have been
removed (rescue completed) and the time is recorded.
Although the present invention has been described with reference to
preferred embodiments, those skilled in the art will recognized
that changes can be made in form and detail without departing from
the spirit and scope of the invention.
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